April 2018 - Msepostdoc-list

Seminar Reminder for David M. Guzman's Ph.D. Final. Seminar: Wednesday, April 18, in ARMS 1109, at 1:00; Exam same day, in ARmS 2009 at 2:00. " Structural, Thermodynamic, Electronic Properties of Mixed Ionic/Electronic Conductor Materials"
by Son, Rosemary E 17 Apr '18

17 Apr '18

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Structural, Thermodynamic, and Electronic Properties of Mixed Ionic-Electronic Conductor Materials" By David M. Guzman Purdue MSE PhD Final Exam Advisor: Professor Alejandro Strachan ABSTRACT Resistive switching electronic devices based on electrochemical metallization (ECM) cells are promising candidates from many beyond-CMOS applications. With the aim of unraveling the physics behind filamentary and threshold switching in ECM cells consisting of solid mixed ionic-electronic conductor electrolytes, this work focused on using first-principles calculations to characterize the structural, thermodynamic, and electronic properties of copper-doped amorphous silicon dioxide and copper-doped germanium-based glassy chalcogenides. The morphology and diffusion of small copper clusters embedded in amorphous silicon dioxide were characterized by density functional theory calculations. The average formation energy of a single copper ion in the amorphous matrix is found to be 2.4 eV. The theoretical predictions show that copper clusters with an equiaxed morphology are always energetically favorable relative to the dissolved copper ions in a-SiO2. Threshold conduction is predicted to be the transport mechanism for glassy sulfides and selenides due to the ability of copper to remain dissolved in the amorphous matrix even at high metal concentration. Furthermore, the charge carrier transport in sulfur and selenium glasses was found to be assisted by defective states derived from chalcogen atoms whose bonds exhibit a polar character. Date: Wednesday, April 18, 2018 Time: 1:00 P.M. Place: ARMS 1109

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FW: A Special Seminar : Professor Grethe Winther, Technical University of Denmark
by Son, Rosemary E 17 Apr '18

17 Apr '18

Dear All Colleagues wanting to meet with Grethe please feel free to let me know. Title: Coupled experiment and modelling to study grain orientation and interaction effects in deformed metals Date: TODAY Time: 10:30 am Coffee/Pastry; 11:00 am Seminar starts Place: ARMS 1103 Thank you, Anter El-Azab - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Anter El-Azab, Professor School of Materials Engineering Purdue University Editor-in-Chief, Materials Theory (Springer-Nature Group) Neil Armstrong Hall of Engineering 701 West Stadium Avenue West Lafayette, IN 47907-2045 Phone: 765-496-6864 Fax: 765-494-1204 E-mail address: aelazab(a)purdue.edu<mailto:aelazab@purdue.edu>

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Seminar Reminder for Travis Thornell's Ph.D. Final Exam. Seminar: Tuesday, April 17, at 9:30 a.m., in ARMS 1028: Exam same day at 10:30, in ARMS 2237
by Son, Rosemary E 16 Apr '18

16 Apr '18

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Synthesis and Characterization of Model Acrylic-based Polymer Gels." By Travis L. Thornell Purdue MSE Ph.D. Final Exam Advisor: Professor Kendra A. Erk ABSTRACT Materials made from polymer gel networks are important to many everyday applications in health care to building materials. These gel materials can be easily synthesized in various ways, but characterizing the overall material mechanics and properties are challenging due to the soft nature of their respective bulk structures. Model acrylic-based copolymer gels were investigated to understand the fundamental characteristics and mechanical properties from different crosslinking and gelation processes. First, model hydrogels with fracture-healing characteristics similar to materials needed for injectable drug delivery systems were studied using shear rheology to determine timescales of fully healed networks. The industrially available gel was a thermoreversible triblock copolymer composed of poly(methyl methacrylate)-poly(n-butyl acrylate)-poly(methyl methacrylate) in 2-ethyl hexanol to form a physical gel from polymer-solvent interactions. A methodology of quantifying healing was developed from an applied constant shear rate and monitoring the shear stress response of the samples. The maximum shear stress responses observed during fracture and re-fracture after allowing the sample to rest indicated gel healing. Given sufficient time, gel healing was determined to be dependent on testing temperature and polymer concentration. The time for fully healed networks was achieved on the order of minutes for the lowest concentration of 5 vol. % at temperatures of 28 and 25°C to several hours for the highest concentration of 6 vol. % at lower temperatures of 23 and 20°C. Lastly, spherical superabsorbent polymer (SAP) gels with silica nanoparticles (SiO2) were synthesized from inverse suspension polymerization to form chemically crosslinked composite hydrogels of polyacrylamide and poly(acrylic acid). The hydrogels were studied for understanding the interaction of SiO2 nanoparticles within polyelectrolyte networks for use as a chemical admixture for internal curing of high performance concrete. The composite SAP hydrogels were produced with bare or silane-functionalized SiO2 particles to investigate the effects on swelling performance, shape, and cement paste microstructure. Date: Tuesday, April 17, 2018 Time: 9:30 A.M. Place: ARMS 1028

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Friday, April 20, 2018 MSE 690 seminar Speaker Professor Maryam Ghazisaeidi, Ohio State University
by Coar, Stacey L 13 Apr '18

13 Apr '18

[cid:image001.png@01D3D348.6188AED0] Stacey Stacey Coar Secretary/Development Assistant School of Materials Engineering Purdue University Neil Armstrong Hall of Engineering 701 West Stadium Ave. Room 2300 West Lafayette, IN 47907 765-494-4100 scoar(a)purdue.edu<mailto:scoar@purdue.edu>

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Seminar Notice for Kayla Yano's Preliminary Exam. Seminar, Friday, April 20, at 2:00, in HAMP 2107; Exam same day, at 3:30, in ARMS 2222
by Son, Rosemary E 13 Apr '18

13 Apr '18

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "In Situ SEM and TEM Size-Effects in Ion Irradiated Materials" By Kayla Haruko Yano Purdue MSE Ph.D. Preliminary Exam Advisors: Professor Janelle P. Wharry and Professor Maria A. Okuniewski ABSTRACT Due to the shallow depth of ion irradiation damage, in situ SEM and TEM mechanical testing has been used to evaluate the irradiation effects on mechanical properties of irradiated materials. In turn, this small-scale testing can experience size-effects due to the microstructure-sample dimension relationship. This literature review provides a brief overview of the existing literature for three different sample geometries: micro-pillar compression, cantilever bending, and beam fracture testing. In depth analyses of the prevailing models for each geometry is also provided. Ultimately, this review concludes that coupling microstructural information with in situ mechanical testing can account for the size-effects in these geometries. Date: Friday, April 20, 2018 Time: 2:00 P.M. Place: HAMP 2107

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Fwd: Dr. Paul L. Wattelet Distinguished Nuclear Engineer Seminar
by Donna Bystrom 13 Apr '18

13 Apr '18

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Seminar Notice for Keyou Mao's Preliminary Exam. Seminar: Thursday, April 19, at 1:00, in ARMS 3115; Exam same day, at 2:30, in ARMS 2009
by Son, Rosemary E 12 Apr '18

12 Apr '18

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Microstructural Characterization and Micromechanical Testing of Laser Weld Repairs on Neutron Irradiated 304 Stainless Steel" By Keyou Mao Purdue MSE Ph.D. Preliminary Exam Advisors: Professor Janelle P. Wharry and Professor Xinghang Zhang ABSTRACT This study is intended for the assessment of microstructural and mechanical integrity of the laser weld repairs to highly neutron-irradiated, helium (He) containing AISI 304 Stainless Steel (SS). To satisfy the demands of the life extensions of Light Water Reactors (LWRs), welding is needed to repair the structural components of the reactor vessels. Conventional welding techniques such as gas tungsten arc welding has high-heat-input, leading the He coalescence into bubbles on the grain boundaries, which exacerbates cracking. The laser welding limits such issue by greatly reducing the heat input. There is consequently a critical need to assess the integrity of these welds for over-extended irradiation service. In this work, single laser welds are made on different plates of 304 SS irradiated in Experimental Breeder Reactor-II (EBR-II) reflector over a range of dose and He concentration conditions: ~1-24dpa with ~0.2-8 appm He, corresponding to ~0.5-2.5% swelling. A combination of transmission electron microscopy and electron backscattered diffraction is utilized to characterize the microstructure of the base, Heat Affected Zone (HAZ) and weld metal, for instance: voids, dislocations, grain structures, precipitates and chemical composition etc. Mechanical integrity in these regions is assessed by three major micromechanical testing methods: 1) Ex-situ and in-situ nanoindentation measures the hardness across the weldment; 2) Scanning Electron Microscopic (SEM) in-situ micropillar compression quantifies the dislocation- -grain-boundary interactions and identifies the deformation and slip transfer mechanisms. 3) SEM in-situ microcantilever beam bending test compares the fracture toughness of single grains dependent on irradiation and welding conditions. Date: Thursday, April 19, 2018 Time: 1:00 P.M. Place: ARMS 3115

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Fwd: FW: Seminar Announcement: Dr. Baratunde Cola / 2018 Viskanta Lecturer / 4:00pm Thursday April 19, 2018 / ME 2054
by Donna Bystrom 11 Apr '18

11 Apr '18

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Seminar Notice for David M. Guzman's Ph.D. Final. Seminar: Wednesday, April 18, in ARMS 1109, at 1:00; Exam same day, in ARmS 2009 at 2:00. " Structural, Thermodynamic, Electronic Properties of Mixed Ionic/Electronic Conductor Materials"
by Son, Rosemary E 11 Apr '18

11 Apr '18

Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Structural, Thermodynamic, and Electronic Properties of Mixed Ionic-Electronic Conductor Materials" By David M. Guzman Purdue MSE PhD Final Exam Advisor: Professor Alejandro Strachan ABSTRACT Resistive switching electronic devices based on electrochemical metallization (ECM) cells are promising candidates from many beyond-CMOS applications. With the aim of unraveling the physics behind filamentary and threshold switching in ECM cells consisting of solid mixed ionic-electronic conductor electrolytes, this work focused on using first-principles calculations to characterize the structural, thermodynamic, and electronic properties of copper-doped amorphous silicon dioxide and copper-doped germanium-based glassy chalcogenides. The morphology and diffusion of small copper clusters embedded in amorphous silicon dioxide were characterized by density functional theory calculations. The average formation energy of a single copper ion in the amorphous matrix is found to be 2.4 eV. The theoretical predictions show that copper clusters with an equiaxed morphology are always energetically favorable relative to the dissolved copper ions in a-SiO2. Threshold conduction is predicted to be the transport mechanism for glassy sulfides and selenides due to the ability of copper to remain dissolved in the amorphous matrix even at high metal concentration. Furthermore, the charge carrier transport in sulfur and selenium glasses was found to be assisted by defective states derived from chalcogen atoms whose bonds exhibit a polar character. Date: Wednesday, April 18, 2018 Time: 1:00 P.M. Place: ARMS 1109

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Seminar Reminder for Daw Gen Lim Ph.D. Final Exam: Seminar Thursday, April 12, in HAMP 1252; Exam 3:30, same day, in ARMS 2237
by Son, Rosemary E 11 Apr '18

11 Apr '18

Please consider attending the following: MATERIALS ENGINEERING SEMINAR “Investigation of Electrochemically Li-ion Active Materials for Li-ion Batteries” By Daw Gen Lim Purdue MSE Ph.D. Final Exam Advisors: Professor Jeffrey P. Youngblood and Professor Vilas G. Pol ABSTRACT Being the battery of the 21st century, Li-ion batteries have been making headway towards replacing traditional medium to large scale energy storage devices. Recent applications ranging from EVs to grid-level energy storage, have driven the design criteria of Li-ion batteries to evolve at a rapid pace. Three major goals are low cost, high electrochemical performance, and better safety. New targets set by the DOE to make Li-ion batteries more competitive in their new market sectors have been to decrease cost to $125 kWh-1 and increase specific gravimetric and volumetric energy density to 235 Wh kg-1, 500 Wh L-1, respectively. Keeping the overall theme of low-cost, high energy density, and improved safety. This thesis presents works on the three major components of a Li-ion battery: sustainable wheat derived-carbon anodes, high capacity V2O5|Graphene nanoplatelets composite cathodes, and rare earth nickelates as a potential solid-state electrolyte for improved safety. Systematic solid-state processing, structural, and electrochemical studies were conducted on wheat derived carbons. Coupling carbonization temperatures and structural evolution of biomass-derived carbons (in this case wheat), lithium insertion properties can be tuned, to create a high capacity and sustainable anode material. An optimal condition presents itself at a carbonization temperature of 600 ˚C with a stable lithiation capacity of 390 mAh g-1. In the Li-ion cell, the limiting factor in the total output capacity (mAh g-1) of the cell is governed mainly by the cathode materials, as cathode materials tend to be lithium-based transitional metal oxides (high density compared to anode materials). Having one of the highest lithium storage capacity, V2O5 is a cathode material that suffers from low electronic conductivity and particle fragmentation upon continuous lithium insertion and extraction. In this work, sonochemistry is utilized in the synthesis of V2O5|Graphene-nanoplatelets (GNPs) composite to improve electronic conductivity and kinetics of lithium-insertion and extraction. Surface modification of the graphene nanoplatelets during sonication of GNPs allow for in situ growth of V2O5 nanoparticles. With the size reduction of the V2O5 particles and the conductive GNPs backbone, the composites achieved 248 mAh g-1 specific cathode capacity; retaining 83% of initial capacity after 50 cycles. The previous two works illustrate strategies to create a low-cost and high electrochemical performance Li-ion battery via sustainable material implementation, structural and morphology control, and composite formation; this final work studies the electrochemical properties of perovskite rare-earth nickelates (specifically SmNiO3) and its integration as a solid-state electrolyte in an all-solid-state lithium-ion battery. Upon insertion of Li+ ion, SmNiO3 undergoes a Mott-transition, simultaneously allowing for a large amount of mobile Li+ to be stored at the interstitial sites (approaching a ratio of one dopant per unit-cell). The combination of a lattice expansion (~10% increase) and the interstitial doping creates a perfect condition for fast Li+ conduction with reduced activation energy. Initial efforts for the integration of the LiSmNiO3 in a solid-state-cell LiCoO2 |LiSmNi|Si results with initial charging capacities reaching 1338 mAh g-1. Date: Thursday, April 12, 2018 Time: 2:30 P.M. Place: HAMP 1252

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